Aspects of the present invention relate generally to the field of video processing, and more specifically to display of a closed caption feature.
In conventional video coding systems, an encoder may code a source video sequence into a set of multiple data streams. For example, coded video may include a video stream, a text or closed caption stream, and an audio stream. Often, the source video is encoded with a plurality of different components. For example, the source video may be encoded with a low-resolution video component, with a high-resolution video component, with subtitles in one or more languages, or with one or more audio tracks.
The subtitle component of coded video data generally consists of coded images that are coded and displayed in accordance with Consumer Electronics Standard (CEA) 608 or CEA-708. CEA-608 and CEA-708 are standards that define methods for coding a text component with associated parameters to control the display of that text. CEA-608 compatible data is much more common than CEA-708 data and so the display of most coded video is limited to the parameters described therein. As set forth in CEA-608, the display area of a frame is divided into 32 columns and 15 rows, creating cells that each holds a single character such that each line may hold 32 characters. Then the size and placement of the text is limited to the height of each row and the width of each column. Then various characters may be placed on the screen based only on their associated cell coordinates. Therefore, data coded according to CEA-608 has limited display options for closed caption text.
Accordingly, there is a need in the art to process closed caption text to provide enhanced features that are otherwise not provided.